Origin and Habitat: Border of San Luis Potosi and Tamaulipas, in the Tampico area. Type locality: Mexico, San Luis Potosi (In the valley, near Estación Villar), in the East part of the state.Habitat and ecology:Astrophytum myriostigma var. strongylogonum dwells on hills covered by shrubs and in the open places, where limestone covers the surface, these plants grow, often along with Turbinicarpus knuthianus and Mammillaria aureilanata.

Description:A. myryostigma var. strogylogonum is a very beautiful form with a larger flower and rounded, non-angular ribs, unlike typical myriostigmas the 5 fat ribs in adult specimens are always rounded and noticeably curved, making quite a contrast among the other myriostigmas. With age horizontal furrows will mark the sides of the ribs as well the midline line between the edges of two contiguous ribs becomes characteristically ondulated. The stems is also usually darker green, strong, compact and flat. However juvenile specimens up to 3-5 years old have sharp ribs and are virtually indistinguishable from other myriostigmas.Note:Astrophytum myriostigma is a very variable taxon that now comprises many form previously considered independent the species or varieties. The plant in cultivation and labeled Astrophytum myriostigma var. strogylogonum are frequently hybrids and shows a wide morphological variability especially regarding the density of the white dots on the stem surface and the shape of stems and ribs. In habitat too pure flat stemmed 'strogylogonum' with wavy, non-angular ribs grow side to side with quite distinct plants, with very acute, almost blade-like ribs, this fall within the natural variation of A. myriostigma, and the var. strogylogonum should be synonymized with A. myriostigma, but it still has a value for a collector because they identify and select plants with particular characters.Flowers: The flowers are larger and purely yellow.Remarks: This variety is very popular among Japanese cactus fanciers, which selected beautiful plants with enhanced “strogylogonum” trait. There is also a pure green form (lacking the white hairy scales) that has been classifieed as Astrophytum myriostigma var. strongylogonum subvar. nudum (Rob.Mey.) Backeb.

Subspecies, varieties, forms and cultivars of plants belonging to the Astrophytum myriostigma group

Astrophytum myriostigmaLem.: It is a spineless solitary plant covered with many white dots. A transverse section of the stem reveal a perfect 5 pointed star shaped form (like the common star-fish) giving the plant the appearance of a bishop's mitre (hence the common name Bishop's cap)

Astrophytum myriostigma f. proliferumhort.: has an abnormal tendency to branch forming small side pups from the areole. In cultivation there are several clones some of them branching like mad, while other almost normal.